We've just watched two failed regimes in three years. Got to be some lessons we can learn from this. I'll get the ball rolling with three obvious ones.
1. Marginalise or sell Rooney. Ferguson did this in his final season by signing RvP and making him the main man upfront and he won the league. Both Moyes and Van Gaal went the opposite direction, they loved Rooney, made him their captain and tried to build the side around him. They both failed and I feel what Mourinho does with Rooney will be the single biggest factor in how well he does at United.
2. Quicker and more athletic players. United play in the fastest and most physically demanding league in the world. Moyes spent all his money on players who couldn't run (Mata and Fellaini) and give a physically declining Rooney a massive new contract. Van Gaal signed some good players in this regard but also brought in guys like Blind, Schweinsteiger, Darmian and relied on the three players I named from the Moyes era way more than he should have. We have simply been physically outmatched time after time post-Ferguson and one of the major pluses I can see for Mourinho is that this doesn't happen to his teams.
3. End the Giggs madness. Being a good player shouldn't automatically mean you become a coach at one of the biggest teams in the world. When the regime you are a coach in fails you shouldn't then get promoted to assistant manager and be lined up for the main job itself. When that regime fails as well... just learn from your mistakes...
What else should we have learned from the past three years?
IMO you are not looking at this from the bigger picture. I see several issues:
1. In the 1990s after Busby died, Fergie made statements that club was governed more professionally and there would be no repeats of the managerial successsion failures of the 7os and 80s. The board had a sprinking of managerial specialists and footballers. It was a similar mix to how Bayern had been developing for decades. However, once the Glazers moved in the whole professional management angle disappeared and we returned to typical English management methods.
2. MUFC is a mega corporation, asking Fergie to find his replacement as he retired was simply a bad management decision. This is the most common failure of large concerns and one of the Most important warnings raised in business schools. Given Fergie's association with business schools it was a bizarre lapse.
3. Moyes was an unmitigated disaster - even on a basic SWOT test Moyes should never even have been on the reserve list.
4. LVG was an example of poor homework. He was a disaster at Bayern, a Neanderthal with Stoneage tactics to quote Mehmet Scholl. His style and methods could never sit well with us even if he had come in after Fergie.
5. There was no compensation for the bad management decisions in buying top quality players. We had learned this lesson in the 70s and 80s but seemed to have forgotten it. In the end the transfer and squad policy has rocked and rolled; and, we creaked from one boring game after another. There are no comparisons to the amount of money we spent and abject level of success - our nemesis is Leicester who spent little, entertained, and won our trophy.
6. The idea of transition became a process of change without time limits. There could be no end ti the state of change as we came 5th to a side that out scored us, but teams like Spurs also out scored us by such a huge margin. The same problem lies with the defence where we're badly stretched. Just how many more players do we need is now a regular debate even though we have gone through bucket loads of money and raised youth to the first team.
7. We have all the talent and its nlw time to place them under a dynamic manager to allow their abilities to show; rather than keeping them boxed up in Stoneage tactics.